Current-rectifying apparatus.



l i l UNITED STATES PATENT GFFICE.

FRANK CONRAD, 0F SWISSVALE, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- 'VANIA.

To all whom 'it may concern.'

.Be it known that I, FRANK CONRAD, a citizen of the United States, and a resident yof Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement' in Current- Rectifying Apparatus, of which the following is a specilication.'

My invention relates to current-rectifying apparatus, and it has for its object to provide means whereby the current following a short circuit in a vapor or other suitable current rectifier will be limited to a comparatively small value, the evil effects of short circuits being thereby substantially eliminated, and the occurrence of the short circuits themselves being substantially prevented.

My invention consists in so arranging the transformer windings through which current is supplied to the rectifying apparatus that the transformers may serve as currentlimiting means upon the occurrence of a short circuit.

The single figure of the accompanying drawing diagrammatically illustrates a rectifier system embodying my invention.

Two mercury-vapor or other suitable current-rectifying devices 1 and 2, having anodes 3 1 and 5 6, respectively, and mercury or other suitable vaporizable cathodes 7 and 8, respectively, are supplied with alternating current through the secondary windings 9, 10, 11 and'12, of transformers 13, 14, 15 and 16, respectively. One terminal of each of the secondary windings is connected to one terminal of a battery 17, or any other suitable receiver of direct current, the other terminal of which is connected to the cathodes 7 and 8 of the rectifiers, suitable inductive devices 18 and 19, respectively, being included in the said connections, for the purpose of sustaining the rectified currents. The remaining terminals of the secondary' windings of the transformers are severally connected to thc anodes of the rectifier-s, the windings $1 and 11 being connected respectively to the anodes 3 and 4'of the rectifier 1, and the windings 10 and 12, respectively, being connected to the anodes 5 and (5 of the rectilier Q. The primary windings 20, 21, 2Q and 23, respectively, of the transformers are connected in series in pairs, the windings 20 and 2l constituting onel pair, and the windings 22 and Specification of Letters Patent.

CURRENT-RECTIFYENG APERATUS.

Patented Sept. 29, 1914.

Application led January 10, 1912. Serial No. 670,523.

constituting the other pair.. The primary windings receive current from any suitable supply circuit 24e-25.

In the normal operation of the System, alternate half-waves of the alternating current are supplied to the rectiers by Way of the anodes 3 and 5, the circuits being completed through the battery 17. The other alternate half-waves are supplied to the rcctifiers through secondary windings 11 and 12 of the transformers, and enter the rectilicrs by way of the anodes 4: and 6, respectively. 1f a short circuit. occurs in one of the rectiiers, the short circuit current will traverse the secondary windings of two of the transformers belonging to di'erent pairs, with the result that a large amount of impedance is introduced into the path of the short circuit current, therelby materially limiting the same. This will be best understood by considering, for example, that ashort circuit occurs in the rectifier 1 between the anodes 3 and 4, in whichcase the short circuit current will traverse the transformer windings 9 and 11. lf, at the same time, the rectilier 2 continues to operate normally. the windings 10 and 12 will alternalclv be inactive, with the result that the primary windings 21 and 23 of the transformers 1i and 16 alternately serve as impedance devices that are included in circuit with the primary windings 2O and 22 of 'the transformers 13 and 15, Vwhich induce the short circuit current in the secondary Windings S) and 11.. The primary current is thus materially limited, and the short circuit is also correspondingly limited. The limitation of the short circuit current prevents injury to the rectier and also substantially prevents the occurrence of the short circuits themselves.

lt will. of course, be understood that if a short circuit occurs in the rectifier 2, the current will be limited in a similar manner. As the possibility7 of the simultaneous short circuiting of both 'the rectifier-sl is extremely remote, the protection afforded by the present system of connections is eiective and reliable. I

l claim as my invention: Y

1. The combination with two rectir'yingY devices, of four transformers the primary windings of which are connected in series in pairs, and the secondary windings of which have a common connection to the cathodes of the rectiliers and other connections respectively to the anodes of the rectiers, the anodes of each rectifier being lrespectively connected to secondary windings of transformers beionging to diil'erent pairs. l

The combination with two rectiiying devices, of four transformers, the primary windings of which are connected in series in pairs,and the secondary windings of which have a common connection to the cathodes of the rectiiers and other connections respectively to the anodos of the reoti- @3. The combination' with two rectiiying devices, each having two anodes and a cathode, of four transformers having primary windings, connected in series in pairs and secondary windings, a terminal of each of which is 'connected to the cathodes of the rectiiers and the remaining terminals oi" which are respectively connected to the anodes of the rectiiiers, the anodes of each rectifier being respectively connected to the secondary windings of transformers belong ing to diiierent pairs. i

e. The combination with a supply circuit end current-rectifying apparatus, of transforming apparatus interposed between the circuit and the curreiitr'ectiiiyirig apparatus, and connections between the current ing apparatus and the transforming apparatus whereby the latter normally oi'ers comparatively little opposition to the iow of current to the rectiiying apparatus, ene. whereby, upon the occurrence of n; short circuit, oliers a large amount of opposition to the iiow of current.

rllhe combination with a supply circuit and two multi-anode 'rectifiers, the transformershaving iry and secondary windings, and coin ons whereby the anodes oi' the rectiiiers are supplied 'from the trans- `ici-.mer secondary windings, the second ary winding of each trensiiorrner .is rendered inactive dn alter-nate half wave nii-.speso cycles of the current, and also whereby short circuit current between two :modes of a rectifier is limited in value by the high reactanoe of inactive secondary windings.

6. The combination with transforming apparatus comprising four sets yof primary and secondary windings, and magnetizable core parts whereby the windings of each set are inductively more closely related to each other than to the windings o other sets, of current-rectii'ying apparatus supplied from the said secondary windings.

'i'. The combination with two rectifying devices, of a plurality of transformers having .iiour secondary windings to which the anodes ot the rectifying devices are respectively connected.

8. The combination with a plurality of transformers having their primary windings connected in series in pairs, of current rectiying apparatus supplied from the secondary windings of the transformers.

9, The combination with a plurality of transformers having substantially inde; pendent magnetic circuits and having their primary windings connected in series in pairs, of current rectifying apparatus supplied rom the secondary windings of the transformers.

l0. The combination with transforming apparatus comprising iour sets of primary and secondary windings, the primary windings o which are connected iu series in pairs, and magnetiza'ole core parts whereby 'the windings or". each set are inductivcly more closely Vrelated to each other than to the windings of other sets, oi' current-rectiying apparatus supplied from the said secondary windings.

In testimony whereof, I have hereunto subscribed my name thif 23rd day of Dec. 1911.

FRANK CONRAD. Witnesses:

Yns ino Snrnrr, 

